"Let a peaceful atom enter every home." So went one of the jokes doing the rounds just after the Chernobyl disaster. It may not apply to Moscow yet, but sometimes the joke gets dangerously close to the truth, according to environmentalists and radiation safety officials.According to Gennady Akulkin, who is in charge of inspecting the safety of Moscow's nuclear installations, the south Moscow Polymetall factory that used to produce highly radioactive torium for the military industry had been dumping its waste into a ravine near the factory premises since the 1960s.Now the ravine is filled with waste. In some places the radiation level on the surface reaches 600 microroentgens per hour, 20 times more than the normal background level. Only an imperfect drainage system separates the dump from the River Moskva."The area is fenced-off, of course," Akulkin said. "Bums live there, but what can one do?"Akulkin said that neither the city budget nor the Russian Nuclear Power Ministry have enough funds to purify the drainage water, though a new American purification technique already in use in Russia could solve the problem. Installing the technology at Polymetall factory would cost 800 million rubles ($408,000), according to a January 1994 estimate.The 800 to 1,200 cubic meters of radioactive waste cannot be removed because of a danger of landslides that could destroy the factory, Akulkin said. "It's Moscow's sickest point as far as radiation safety goes," Akulkin said in a telephone interview Thursday. But it is by no means the only dangerous one.The number of nuclear installations, including reactors, in Moscow is being assessed differently by different organizations. Gosatomnadzor, the federal nuclear safety control body, puts it at 49. Akulkin said it was 43. All of these installations are research facilities, as Moscow has no nuclear power plants.The installations have been producing nuclear waste for years. Most of the waste, classified by both environmentalists and government bodies as low-grade with a radiation level of 100 microroentgens per hour, was taken out of Moscow until 1989, when the Moscow region authorities forbade the city to bury nuclear waste in the suburbs. Waste has since been buried within city limits.According to Akulkin, there are 18 sites in Moscow where low-grade radioactive waste has been plowed under a thin layer of "clean" soil. They are mostly located on the city's outskirts."It's all right as long as it's far away from residential buildings," Akulkin said. "Trouble would only start if there was new construction on these sites."But environmentalists believe that the dumping sites are more dangerous than officials let on. "The storage sites are old," said Lika Galkina of Greenpeace Moscow office. "And there are the subterranean waters underneath."Several reactors and their waste-storage facilities are close to densely populated areas. Moscow's biggest research reactor, at the Kurchatov Institute, is located in a residential area in the western part of the city. According to Akulkin, there has been little work for the reactor lately, but it would be very costly to remove it from the site.Akulkin said it would take 15 billion rubles ($7 million) to remove radioactive waste from Moscow and dismantle unused reactors.Other potential dangers come from two Moscow research institutes whose reactors used to enrich uranium for nuclear power plants. The production has been stopped, but 65 tons of uranium ore is still in storage at the facilities. "The big question is, what should we do with it now?" Akulkin said.